This invention relates to an improved post anchor and in particular to a post anchor having an improved method of securing a post to the anchor.
Posts, such as sign posts, fence posts etc, are typically held in the ground by digging a hole, placing the post in the hole and filling the hole with concrete or firmly compacted soil. This process is effective but time consuming. Furthermore, any impact to the post results in damage which can only be corrected by complete removal of the post and repositioning of a new post following the same procedure.
The above procedure has proven to be particularly unsuitable for posts carrying road signs or other similar situations. This unsuitability is due to the high incidence of damage which can occur with road signs. For example, a Keep Left sign will be subject to a high probability of damage due to a vehicle failing to adequately respond to the keep left direction. In the case of a vehicle impacting a sign, the sign must be completely removed and replaced. As mentioned above, this is a time consuming and therefore expensive process.
The problem has been addressed in the prior art by providing post anchors which are decoupled from the post. In the prior art, a number of examples exist of a post anchor which is independently driven into the ground at a location in which a post is to be positioned. The post is then associated with the post anchor by some form of clamping means. Typically, the post anchor is a finned assembly made from pressed mild steel.
In the simplest form, the post is welded to the top of the post anchor once the post anchor has been driven into the ground. Other arrangements have been developed in which a cup is provided at the top of the post anchor into which the post is seated. Fixing arrangements between the cup and the post include bolts and rivets for metal poles or nails for wooden poles. It is also known to provide spikes on the inside wall of the cup to capture wooden poles that are driven into the cup.
Other arrangements include clamping systems to associate the post with the cup. In this solution the post is inserted into the cup and a wedge is driven between the post and the cup to firmly associate the post with the post anchor. An example of this form of association can be found in Australian Patent Application number 52067/98 in the name of Impact Post Anchors Pty Ltd.
The prior art methods of associating a post with a post anchor have proven to be of limited effectiveness. In particular, the wedging arrangement described in the above mentioned publication has elements extending beyond the confines of the post anchor or the post. These elements can be dangerous to persons and property moving in the vicinity of the post and post anchor. Furthermore, the fastening arrangement is aesthetically unpleasing.
A more suitable manner of securing a post to a post anchor is desirable.
It is an object of the present invention to provide a means for associating a post with a post anchor.
Further objects of the invention will be evident from the following description.
In one form, although it need not be the only or indeed the broadest form, the invention resides in an improved post anchor comprising:
a ground engaging portion comprising two or more fin members;
a post receiving portion comprising two or more collets located between upper portions of said two or more fin members, said collets defining a space dimensioned to receive a post to be associated with said post anchor; and
a clamping member adapted to locate around said collets and urge said collets towards engagement with said post when said post is seated in the space.
The ground engaging portion is suitably a stake formed from pressed metal fins that are welded together.
In preference the collets define a cylindrical space and the clamping member is a cup shaped member that sits over the collets. This arrangement suits common cylindrical posts.
Alternatively, the collets may define a rectangular space and the post may have a rectangular cross section adapted to seat in the space defined by the collets.
Suitably the ground engaging portion comprises four fin members and there are four corresponding collets located between upper portions of the fin members.
In the case of collets defining a rectangular space the collets may each define a side of the rectangular space or alternatively may define a corner of the rectangular space.
In one form, the clamping member is forced to locate around the collets by applied force, such as hammering. In an alternate form the clamping member may be screwed on to the collets.
The clamping member may be suitably tapered so to apply increasing pressure to the collets as it is forced into location.
In preference, a ridge is formed towards the top of each collet so that the collet is urged into the space as the clamping member is located around the collets.